Big needle jumps in psychotherapy research.

The field of psychotherapy research has come a long way since its inception. In addition to foundational data on psychotherapy's general efficacy and effectiveness, there has been steadily mounting evidence to answer questions, such as how, for which patients, when delivered by which therapists, and under what conditions does psychosocial treatment work? Moreover, there have been key methodological and data analytic developments over time, which have supported or catalyzed, respectively, more nuanced or new psychotherapy knowledge. Nonetheless, given the field's relatively young age, as well as the need for greater replication of results, better science-practice integration, and higher consensus on psychotherapy's core and consensual scientific principles, the field arguably remains somewhat immature and in need of more empirical advancements to meet the ever-rising need for effective mental health care. Such progressions will often come in incremental steps; however, "big needle movements" are also needed to embody or set the stage for more revolutionary changes in how we study, understand, and practice psychotherapy. To this end, the articles in the present special section exemplify such innovations through their big-impact results and/or promising proof-of-concept methods. In this introduction to the section, we summarize the sizeable potential of the nine included articles to influence and inspire the field of psychotherapy. (PsycInfo Database Record (c) 2025 APA, all rights reserved).